Of course they could, in fact it'll probably be great prep if they read it and understand it instead of just memorising the answer.

If they just memorise the answer any smart teacher can trip them up by just rephrasing things or developing tangents to see understanding.

In school before exams, I'd often make little cheat sheets about things that you'd need to memorise like formulas for areas and volumes or certain physics equations (we weren't allowed any reference material for that on exams). The very act of writing them all down before the exam would often boost my memory enough to the point I'd just recall them.